JavaWeb实现具体分页封装

港控/mmm° 2022-02-15 09:52 459阅读 0赞

## 一、准备工作 ##

**1、jar包：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70]  
a. spring依赖包  
spring-tx-5.0.0.RELEASE.jar  
spring-jdbc-5.0.0.RELEASE.jar  
spring-core-5.0.0.RELEASE.jar  
spring-beans-5.0.0.RELEASE.jar  
commons-logging-1.2.jar

b. mysql驱动包及连接池依赖  
mysql-connector-java-5.1.37-bin.jar  
druid-1.0.9.jar

c. 请求参数封装包  
commons-beanutils-1.8.0.jar

d. jsp依赖包  
javax.servlet.jsp.jstl.jar  
jstl-impl.jar

**2、js依赖**  
![在这里插入图片描述][2019042411194986.png]  
a. jquery框架依赖文件  
b. bootstap框架依赖文件

## 二、代码实现 ##

**1、jdbc配置**

导入jar包 ：  
druid依赖包：druid-1.0.9.jar  
mysql驱动包： mysql-connector-java-5.1.37-bin.jar

配置文件：druid.properties

# 驱动
    driverClassName=com.mysql.jdbc.Driver
    # 数据库地址
    url=jdbc:mysql://127.0.0.1:3306/my_db
    # 用户名
    username=root
    # 密码
    password=root
    # 初始化连接数量
    initialSize=5
    # 最大连接数
    maxActive=10
    # 最大等待时间
    maxWait=3000

创建JDBCUtils工具类

package com.mollen.demo03;
    
    import com.alibaba.druid.pool.DruidDataSourceFactory;
    import javax.sql.DataSource;
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.Properties;
    
    /**
    * @ClassNmme:      JDBCUtils
    * @Author:         Mollen
    * @CreateDate:     2018-09-07 16:44:42
    * @Description:
    *          Druid连接池工具类
    */
    public class JDBCUtils {
        /**
         * 1.定义成员变量
         */
        private static DataSource ds;
    
    
        /**
         * 2.加载数据源
         */
        static {
            try {
                Properties pro = new Properties();
                InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("Druid.properties");
                pro.load(is);
                ds = DruidDataSourceFactory.createDataSource(pro);
            } catch (IOException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        /**
         * 3.获取连接池对象
         * @return
         */
        public static DataSource getDataSource() {
            return ds;
        }
    
    
        /**
         * 4.获取数据库连接对象
         * @return
         * @throws SQLException
         */
        public static Connection getConnection() throws SQLException {
            return ds.getConnection();
        }
    
    }

注意：  
1、参数解释，注意参数类型;  
2、执行语句选择  
增，删，改(DML)操作建议使用executeUpdate();  
查询(DQL)操作建议使用executeQuery() ;  
需要对执行语句类型做出判断用execute()  
3、数据库连接使用完毕必须释放资源

**2、实体类Model层封装**

package com.mollen.model;
    
    /**
     * @ClassName: User
     * @Auther: Mollen
     * @CreateTime: 2018-09-29  16:47:33
     * @Description: User实体类
     */
    public class User {
    
        /**
         * 1.属性
         */
        private int id;				//id
        private String name;		//姓名
        private String gender;		//性别
        private int age;			//年龄
        private String address;		//地址
        private String qq;			//qq
        private String email;		//email
        private String userName;	//账号
        private String passWord;	//密码
    
    		//2.toString
    			...
    		//3.getter/setter
    			...
    		//4.无参构造
    			...
    		//5.有参构造
    			... 
    }

**3、分页工具类封装**

package com.mollen.domain;
    
    import java.util.List;
    
    /**
     * @ClassName:      PageBean
     * @Auther:         Mollen
     * @CreateTime:     2018-10-08  14:57:35
     * @Description:    分页属性封装类：PageBean
     */
    public class PageBean<T> {
        private int totalCount;     //总纪录数
        private int totalPage;      //总页码
        private List<T> list;       //每页的数据
        private int currentPage;    //当前的页码
        private int rows;           //每页显示的纪录数
        
    	//2.toString
    		...
        //3.getter/setter
        	...
        //4.无参构造
        	...
        //5.有参构造
        	... 
    }

**4、Dao数据持久化层**

-------------------UserDao------------------------------
    
    package com.mollen.dao;
    
    import com.mollen.domain.User;
    import java.util.List;
    import java.util.Map;
    /**
     * @ClassName:      UserDao
     * @Auther:         Mollen
     * @CreateTime:     2018-09-29  18:14:39
     * @Description:
     *                  UserDao用户操作接口
     */
    public interface UserDao{
        /**
         * 1.分页查询用户
         */
        List<User> findUserByPage(int start , int rows,Map<String, String[]> condition);
    
        /**
         * 2.统计总记录数
         */
        int totalCount(Map<String, String[]> condition);
    }
    
    
     -------------------UserDaoImpl------------------------------
    
    
    package com.mollen.dao.impl;
    
    import com.mollen.dao.UserDao;
    import com.mollen.domain.User;
    import com.mollen.utils.JDBCUtils;
    import org.springframework.jdbc.core.BeanPropertyRowMapper;
    import org.springframework.jdbc.core.JdbcTemplate;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    import java.util.Set;
    
    /**
     * @ClassName: UserDaoImpl
     * @Auther: Mollen
     * @CreateTime: 2018-09-29  18:14:59
     * @Description: UserDao用户操作实现类
     */
    public class UsereDaoImpl implements UserDao {
        /**
         * 创建JdbcTemplate对象
         */
        JdbcTemplate jtl = new JdbcTemplate(JDBCUtils.getDataSource()); 
        
    	/**
         * 1.统计总纪录数
         * @param condition：封装查询参数
         * @return
         */
        @Override
        public int totalCount(Map<String, String[]> condition) {
            //1.定义模板初始化sql
            StringBuilder sb = new StringBuilder("select count(*) from user where 1 = 1 ");
            //2.定义参数的集合
            List<Object> params = new ArrayList<Object>();
            //3.遍历参数集合,追加查询条件
            Set<String> keySet = condition.keySet();
            for (String key : keySet) {
                //排除分页条件参数
                if("currentPage".equals(key) || "rows".equals(key)){
                    continue;
                }
                //获取value
                String value = condition.get(key)[0];
                //判断value是否有值
                if(value != null && !"".equals(value)){
                    //有值
                    sb.append(" and "+key+" like ? ");
                    params.add("%"+value+"%");
                }
            }
            //4.返回查询结果
            return jtl.queryForObject(sb.toString(),Integer.class,params.toArray());
        }
    }
         
        /**
         * 2.分页查询
         * @param start：记录开始位置
         * @param rows：每页显示条数
         * @param condition：封装查询参数
         * @return
         */
        public List<User> findUserByPage(int start, int rows,Map<String, String[]> condition) {
    		//1.定义sql模板
    		StringBuilder sb = new StringBuilder("select * from user  where 1 = 1 ");
    		//2.定义参数集合
    		List<Object> params = new ArrayList<Object>();
    		//3.遍历参数集合,追加查询条件
    		Set<String> keySet = condition.keySet();  
    		for (String key : keySet) {
    			//跳过分页参数
    			if("currentPage".equals(key) || "rows".equals(key)){
    				continue;
    			}
    			//获取查询参数
    			String value = condition.get(key)[0];
    			//判断是否为空
    			if(value != null && !"".equals(value)){
    				//不为空给sql追加条件
    				sb.append(" and "+key+" like ?  ");
    				params.add("%"+value+"%");
    			}
    		}
    		//添加分页查询
    		sb.append(" limit ?,? ");
    		//添加分页查询参数值
    		params.add(start);
    		params.add(rows);
    		//4.返回查询结果
    		return jtl.query(sb.toString(),new BeanPropertyRowMapper<User>(User.class),params.toArray());
        }

**5、Service服务层**

-------------------UserService------------------------------
    package com.mollen.service;
    
    import com.mollen.domain.PageBean;
    import com.mollen.domain.User;
    import java.util.List;
    import java.util.Map;
    
    /**
     * @ClassName:      UserService
     * @Auther:         Mollen
     * @CreateTime:     2018-09-29  19:47:54
     * @Description:
     */
    public interface UserService {
        /**
         * 1.分页查询
         */
        PageBean<User> findUserByPage(int currentPage, int rows,Map<String, String[]> condition);
    
    }
    
     -------------------UserServiceImpl------------------------------
    
    package com.mollen.service.impl;
    
    import com.mollen.dao.impl.UsereDaoImpl;
    import com.mollen.dao.UserDao;
    import com.mollen.domain.PageBean;
    import com.mollen.domain.User;
    import com.mollen.service.UserService;
    import org.junit.jupiter.api.Test;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @ClassName: UserServiceImpl
     * @Auther: Mollen
     * @CreateTime: 2018-09-29  19:51:14
     * @Description: UserServiceImpl
     */
    public class UserServiceImpl implements UserService {
    
        UserDao userDao = new UsereDaoImpl();
        
        /**
         * 1.分页查询
         * @param start
         * @param rows
         * @return
         */
        @Override
        public PageBean<User> findUserByPage(int currentPage, int rows,Map<String, String[]> condition) {
            //统计总条数
            int totalCount = userDao.totalCount(condition);
            //计算总页数
            int totalPage = (int)Math.ceil(totalCount*1.0 / rows);
            //计算开始索引
            int start=(currentPage-1)*rows;
            //查询当前页显示数据
            List<User> list = userDao.findUserByPage(start, rows,condition);
            //将数据封装到PageBean并返回
            return new PageBean<User>(totalCount,totalPage,list,currentPage,rows);
        }
    }

**6、后台控制逻辑Controller层**

package com.mollen.controller;
    
    import com.mollen.domain.PageBean;
    import com.mollen.domain.User;
    import com.mollen.service.UserService;
    import com.mollen.service.impl.UserServiceImpl;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    import java.util.Map;
    
    @WebServlet("/findUserByPageServlet")
    public class FindUserByPageServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            this.doGet(request, response);
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //1.乱码处理
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/html;charset=utf-8");
    
            //2.获取分页参数
            int currentPage =  Integer.parseInt(request.getParameter("currentPage")==null?"1":request.getParameter("currentPage"));
            int rows =  Integer.parseInt(request.getParameter("rows")==null?"5":request.getParameter("rows"));
    
            //3.获取查询参数集合
            Map<String, String[]> condition = request.getParameterMap();
    
            //3.执行查询操作
            UserService service = new UserServiceImpl();
            PageBean<User> pageBean = service.findUserByPage(currentPage, rows,condition);
    
            //4.转发
            request.setAttribute("pageBean",pageBean);
            request.setAttribute("condition",condition);
            request.getRequestDispatcher("/list.jsp").forward(request,response);
        }
    }

**7.、页面显示View层**

<%--
      Created by IntelliJ IDEA.
      User: Mollen
      Date: 2018/9/30
      Time: 14:31
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <!DOCTYPE html>
    <html>
    <head>
        <title>用户显示</title>
    
        <meta charset="utf-8"/>
        <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
        <meta name="viewport" content="width=device-width, initial-scale=1"/>
    
        <link href="css/bootstrap.min.css" rel="stylesheet">
        <script src="js/jquery-2.1.0.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
    
        <style type="text/css">
            td, th {
                text-align: center;
            }
        </style>
    </head>
    <body>
    <div style="margin: 0 auto;width: 70%">
    
        <div style="margin: auto;text-align:center">
            <h3>用户信息显示</h3>
            <br>
        </div>
    
        <div style="float: left;">
            <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
                <div class="form-group">
                    <label for="exampleInputName2">姓名</label>
                    <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2">
                </div>
                <div class="form-group">
                    <label for="exampleInputName3">籍贯</label>
                    <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3">
                </div>
    
                <div class="form-group">
                    <label for="exampleInputEmail2">邮箱</label>
                    <input type="email" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2">
                </div>
                <button type="submit" class="btn btn-default">查询</button>
            </form>
        </div>
    
        <div style="float: right;margin: 5px;">
            <a class="btn btn-primary" href="save.jsp">添加联系人</a>
            <a class="btn btn-primary" href="add.html">删除选中</a>
        </div>
    
        <div>
            <form id="form" action="" method="post">
                <table border="1" class="table table-bordered table-hover">
                    <tr class="success">
                        <th><input type="checkbox" id="firstCb"></th>
                        <th>编号</th>
                        <th>姓名</th>
                        <th>性别</th>
                        <th>年龄</th>
                        <th>籍贯</th>
                        <th>QQ</th>
                        <th>邮箱</th>
                        <th>操作</th>
                    </tr>
                    <c:forEach items="${pageBean.list}" var="user" varStatus="s">
                        <tr>
                            <td>
                                <input type="checkbox" name="uid" value="${user.id}">
                            </td>
                            <td>${s.count}</td>
                            <td>${user.name}</td>
                            <td>${user.gender}</td>
                            <td>${user.age}</td>
                            <td>${user.address}</td>
                            <td>${user.qq}</td>
                            <td>${user.email}</td>
                            <td>
                                <a class="btn btn-default btn-sm" href="/newLogin/findUserByIdServlet?id=${user.id}">修改</a> 
                                <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id})">删除</a>
                            </td>
                        </tr>
                    </c:forEach>
                </table>
            </form>
        </div>
    
        <div>
            <nav aria-label="Page navigation">
                <ul class="pagination">
    
                    
                    <c:if test="${pageBean.currentPage == 1}">
                        <li class="disabled">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pageBean.currentPage}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                                <span aria-hidden="true"> « </span>
                            </a>
                        </li>
                    </c:if>
                    <c:if test="${pageBean.currentPage != 1}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pageBean.currentPage - 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                                <span aria-hidden="true"> « </span>
                            </a>
                        </li>
                    </c:if>
    
                    
                    <c:forEach begin="1" end="${pageBean.totalPage}" var="i" >
                        <c:if test="${pageBean.currentPage == i}">
                            <li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                        </c:if>
                        <c:if test="${pageBean.currentPage != i}">
                            <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                        </c:if>
                    </c:forEach>
    
                    
                    <c:if test="${pageBean.currentPage == pageBean.totalPage}">
                        <li class="disabled">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pageBean.currentPage}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                                <span aria-hidden="true"> » </span>
                            </a>
                        </li>
                    </c:if>
                    <c:if test="${pageBean.currentPage != pageBean.totalPage}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pageBean.currentPage + 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                                <span aria-hidden="true"> » </span>
                            </a>
                        </li>
                    </c:if>
    
                    <span style="font-size: 25px;margin-left: 5px;">
                        共${pageBean.totalCount}条记录，共${pageBean.totalPage}页
                    </span>
                </ul>
            </nav>
        </div>
    </div>
    </body>
    </html>

## 实现效果如下： ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70 1]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70 2]  
原文：[https://blog.csdn.net/mollen/article/details/83023379][https_blog.csdn.net_mollen_article_details_83023379]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70]: /images/20220215/17ed6c32c7b74d76852bad763c453f43.png
[2019042411194986.png]: /images/20220215/c8ed76b305024f75960080a087dbe40b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70 1]: /images/20220215/6f031ba5441b42938a144ca550b756a1.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3poYW5nMTUwMTE0_size_16_color_FFFFFF_t_70 2]: /images/20220215/8641d2d320f44f9c863ac935701b199b.png
[https_blog.csdn.net_mollen_article_details_83023379]: https://blog.csdn.net/mollen/article/details/83023379